Coherent optical Orthogonal Frequency Division Multiplexing (CO-OFDM) has been demonstrated in fiber optic transmission, beyond 1 Tb/s per wavelength. Optical Fiber nonlinearity is a prominent obstacle to practical implementation of CO-OFDM. The conventional thinking is that OFDM has high peak-to-average power ratio (PAPR) and because nonlinear effects within fiber that cause signal distortion scale with optical power, CO-OFDM must suffer from greater signal distortion.